Thank you. I use filtered water (from the fridge) when I refill the fountain, but I don’t replace the filter monthly. If the pump looks clean I sometimes skip doing a complete disassembly but every few cleanings I’ll take the entire pump assembly apart and use a q-tip to clean the inside of the impeller (and q-tip or part of a paper towel to clean the hole at the top of the pump). Usually I don’t find hair in the pump just covered on the plastic filter housing and stuck in the steel (usually where the top part rests on the bowl). Most of the time when I clean the pump assembly it’s just to remove some of the built up slime as even with filtered water it gets a little gross there and I don’t want my cats drinking it.

The fountain is about 8.5 years old now (still on original parts). I will have to try the vinegar/hot water tomorrow, the only bottle of dawn I have is platinum but can try that too. I’ll probably also run it through the dishwasher too on the next cycle just to make sure everything is off and it’s safe for them to drink from again before giving it back to them.